Common JEE Mistakes

Common JEE Mistakes

### Mistake 1

Using mirror formula for lenses.

### Correct Relations

Mirror:

$$\frac1f=\frac1v+\frac1u$$

Lens:

$$\frac1f=\frac1v-\frac1u$$

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### Mistake 2

Forgetting sign convention in optics.

### Correct Approach

Use Cartesian sign convention.

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### Mistake 3

Confusing power and focal length.

### Correct Relation

$$P=\frac1f$$

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### Mistake 4

Using critical angle formula for wrong medium.

### Correct Relation

$$\sin C=\frac{\mu_{rarer}}{\mu_{denser}}$$